ID: 38 - Protocol violating SOL retries when talking to SIMSO-HTC

c&p from the ticket:
~~~
When I try to use CVS-ipmitool on Ubuntu 8.04 x86_64 to talk to a SuperMicros
SIMSO-HTC (Rev. 2.5, IPMI 2.0) chip on a X7SBi-Board via SOL I often get doubled
characters when typing fast, making the SOL interface basically unusable for
anyone accustomed to using a keyboard for longer than a month ;)

At first I thought this was an issue with SuperMicros implementation of the
protocol and/or the flow control
setup on the machine, but their own app works fine (but not the Linux CLI, which
is maybe
based on ipmitool?). But after reading the IPMI 2.0 SOL specs and watching the
debug output for a bit, it seems that is really an issue with lanplus-SOL
protocol implentation of ipmitool in general.

Specifically, in lanplus.c:ipmi_lanplus_send_payload, when waiting for a SOL
response the case that a non SOL packet is returned is not being
checked. Also the "if (is_sol_packet(rsp) && rsp->data_len)" branch does
terminate with a break, but instead goes for a send try, that seems
counterintuitive, Both these things cause doubled characters for me.

The attached patch seems to solve these issues in my case, but I don't claim to
fully understand your protocol code and/or the protocol, so maybe it will cause
problems elsewhere, especially under packet loss conditions.
~~~

src/plugins/lanplus/lanplus.c

@@ -2369,6 +2369,10 @@ ipmi_lanplus_send_payload(
 
 			rsp = ipmi_lanplus_recv_sol(intf); /* Grab the next packet */
 
+			if (!is_sol_packet(rsp)) {
+				break;
+			}
+
 			if (sol_response_acks_packet(rsp, payload))
 				break;
 
@@ -2381,6 +2385,7 @@ ipmi_lanplus_send_payload(
 				intf->session->sol_data.sol_input_handler(rsp);
 				/* In order to avoid duplicate output, just set data_len to 0 */
 				rsp->data_len = 0;
+				break;
 			}
 		}